Running balanced. Difference between XLR vs. RCA.

Guys, thanks for your input. I'm going to go ahead and try the XLR's first and see if I like the results. Those W-10's are just amazing. They really brought my speakers to life. I'm on the path to the next level... Yea!

I've purchased a pair of Simaudio W-10 mono blocks and P-5 preamp. The manufacturer suggests either interconnects, XLR or RCA, for balanced operation. From the little amount I know of balanced operation... it takes both signals (+ and -) and only amplifies the difference of what is 180 degrees out of phase? Thereby cancelling any added noise? Can it do this with RCA? The manufacturer says if you aren't running in a balanced mode then use only the + input with RCA, and cap the un-used - input, as long as your preamp doesn't invert the signal. If running balanced mode with RCA then use + and -. Of course it does have XLR capabilities also. I contacted Simaudio on this with no recommendations, just some suggested cables. Wanted to get some info from the Audiogoner's experts, and then audition some cables, and let my ears make the final conclusion. Thanks for the responses.